Electrical ignition system



Feb. 5, 1952 w. B. SMITS 2,584,507

ELECTRICAL IGNITION SYSTEM Filed June 16, 1950 Patented Feb. 5, 1952 ELECTRICAL IGNITION SYSTEM Wytz'e Beye Smits, Voorburg, Netherlands, "assignor to Smitsvonk N. V., Rijsw'ijk (Z. H.),

Netherlands Application June 16, 1950, Serial No. 168,439 In the Netherlands July 1, 1949 Claims.

The invention relates to an electrical ignition system, in particular for the ignition of the burner of a boiler, a jetmotor, a gasturbine or like device, comprising a spark plug, at least two condensers and means for loading said condensers. It has for its object to provide a sys-- tem which is adapted to produce periodically two or more sparks in rapid succession, of which sparks the first serves the purpose or atomizing fuel accumulated in or on the active surface of the spark plug and the next sparks ignite the atomized fuel.

In already constructed systems the condensers are successively brought into operation by means of a mechanically or electromagnetically operated switcharm which is moved along a series of fixed contacts. In that case the frequency of the sparks depends on the velocity with which the switcharm is moved. However, since the switcharm has to move through a relatively great distance for contacting a number of contacts, said velocity, that means the frequency of the sparks, greatly depends on the friction to overcome during the movement of the switcharm. Especially when electromagnetically operated switches having more than one pair of cooperating contacts are used said period may vary considerably, which is a disadvantage indeed, since for a predetermined construction of the igniter, a certain fuel and other predetermined conditions, a stable period between the first spark and the second one is required to obtain the highest possible eilect.

The object of the invention is to provide a system which amply meets the above requirements in a practical way. It consists in that the system is provided with means enabling at least two condensers being discharged successively through the igniter or spark plug in order to produce two or more igniting sparks in succession and that the discharge of each condenser, except that the last one, causes the discharge of the next condenser. It has been found that in this manner a substantially constant interval between the various sparks may be obtained.

In order to attain the above mentioned object the winding of a relay may be inserted in the discharge circuit of at least one of the condensers, for instance the first condenser. The contacts of this relay may be inserted either directly in the discharge circuit of the next condenser or in the circuit of the coil of a second relay connected to a current source, the contacts of said second relay lying in the discharge circuit of the next condenser. The second possibility may be used when between the first spark and the second spark a relatively great lag of time is required.

If the intervals between the sparks should be rather long one or more relays having adjustable time lag means may be used.

It is not necessary that relays be used. Relays having partly an electrical and partly a mechanical operation may be too slow in some cases. In these cases pure electrical means, such as circuits comprising spark gaps and/or gas discharge tubes either having or without controlling electrodes may be used instead of said relays.

For the elucidation of the invention reference is made to the accompanying drawing illustrating in Figs. 1, 2 and 3 circuit connections of three different ignition systems according to the invention.

In Fig. 1 of the drawing I designates a battery, 2 is a switch, 3 and 4 are cooperating contacts of an electro-magnetical interrupter, 5 is the coil of said interrupter, 6 is the primary winding of an ignition coil and 1 is a condenser parallel to the cooperating contacts 3 and 4. The device I-'! is a generator of current impulses. When the switch 2 is closed the interrupter will oscillate and a pulsating direct current will be sent through the primary winding 6. The alternating component of this direct current is induced in the secondary winding 8' and serves the purpose of charging the two condensers 9 and I6. To this end these condensers are con nected to said secondary winding 8 through rectifie'rs ll, l2 and I3. The condenser 9 is connected to a spark plug l6 through a predetermined but adjustable spark gap l4 and the coil 15 of a relay. This relay has a pair of cooperating contacts ll, I8 through which the condenser Id may be connected to said spark plug I6. This system operates as follows:

When the switch 2 is closed, the condensers Si and Ill are charged. As soon as condenser 9 reaches a certain voltage the spark gap 14 is ruptured and the condenser is discharged through the plug 16 producing a spark across the points of same. The discharge current flows through the coil I5 of the relay and causes the contact H thereof to close on the contact 18. The result thereof is that the spark plug 16 is shunted to condenser H], which is also discharged through said spark plug, so that a second spark is produced. The interval between the first and the second sparks is determined by the operation of the relay l5, l1, l8, which may operate instantaneously or may be provided with time lag means.

The system according to Fig. 2 corresponds to that according to Fig. 1. However, in this system of Fig. 2 three condensers are used for the generation of three sparks in rapid succession. In the discharge circuit of the condenser 18 the winding iii of a second relay is inserted, through the contacts 20, 2! of which the third condenser 22, which is periodically charged through a rectifier 23, may be connected to the spark plug it. In this system the current required for the second igniting spark energizes the relay 9, so that it closes its contacts 2!), 2! and connects the third condenser 22 to the spark plug, which is then also discharged through the spark plug.

In the system according to Fig. 3 the contacts 17, !8 of the relay i and the contacts 221, 2! of the relay it are inserted in the supply circuits of individral relays, for instance time lag relays 24 and of which the contacts 2? 28, 25, respectively, are in the discharge circuit of the condenser and in that of the condenser 22, respectively. The relay 2 and 25 are supplied with current through the contacts ll, !8 and 2a of the relays l5 and i5, respectively, by a battery This battery may be the same as the battery I which energizes the primary circuit.

What I claim is:

1. In an electrical ignition system, an ignition coil, a primary circuit for supplying variable electro-motive forces to the primary of the ignition coil, an igniting device, a secondary circuit including a first condenser charged from the secondary of the ignition coil and adapted to discharge through the igniting device, a second condenser also charged from the secondary of the ignition coil, a branch circuit from the second condenser to the ignition device and ineluding a spark intensifying gap, and time delay means operated by the discharge of the second condenser for connecting the first condenser to the igniting device.

2. In an electrical ignition system, an ignition coil, a primary circuit for supplying variable electro-motive forces to the primary of the ignition coil, a relay, a secondary circuit including the secondary of the ignition coil, the contacts of the relay and an ignition device, a first condenser shunted across the secondary of the ignition coil, a branch circuit from one side of the secondary of the ignition coil to the ignition device and including a spark intensifying gap and the winding of the relay, and a second condenser shunted between the other side of the secondary of the ignition coil and the branch circuit.

3. In an electrical ignition system, an ignition coil, a primary circuit for supplying variable electro-motive forces to the primary of the ignition coil, a relay, a secondary circuit including a first rectifier, the contacts of the relay and an ignition device, a first condenser shunted across the secondary of the ignition coil and the first rectifier, a branch circuit extending from one side of the secondary of the ignition coil and including a second rectifier, a spark intensifying ga and the winding of the relay, and a second condenser shunted between the other side of the secondary of the ignition coil and the branch circuit.

4. In an electrical ignition system, an ignition coil, a primary circuit for supplying variable electro-motive forces to the primary of the ignition coil, a first relay, a secondary circuit including the secondary of the ignition coil, the contact of the first relay an ignition device, a first condenser shunted across the secondary of the ignition coil, a second relay, a first branch circuit from one side of the secondary of the ignition coil to the ignition device and including the winding of the first relay and the contacts of the second relay, a second condenser shunted from the other side of the secondary of the ignition coil in the first branch circuit, a second branch from the one side of the secondary or" the ignition coil to the ignition device and including spark intensifying gap and the winding of the second relay, and a third condenser shunted from the said other side of the secondary of the ignition coil to the second branch circuit.

5. In an electrical ignition system, an ignition coil, a primary circuit for supplying variable electro-motive force to the primary of the ignition coil, first and second time delay master relays, first and second slave relays, respectively, parallel local circuits for the slave relays including a. source of electro-motive force and the contacts, respectively, of the master relays and the windings, respectively, of the slave relays. a secondary circuit including the secondary of the ignition coil, the contacts of the first slave relay, the Winding of the econd master relay, and an ignition device, a first condenser shunted across the secondary of the ignition coil, 2, first branch circuit from one side of the secondary of the ignition coil and including the contacts of the second slave relay and the ignition device, a second condenser shunted from the ot er side of the secondary of the ignition coil to the first branch circuit, a second branch from the one side of the secondary of the ignition coi to the ignition device and including a spark intensifying gap and the winding of the first master relay, and a third condenser shunted from the other side of the secondary of the ignition coil to the second branch circuit.

vVYTZE BEYE SMITS.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,745,830 Bethenod Feb. 4, 1930 2,470,413 Ramsay May 17, 1949 2,503,054 Laird Apr. 4, 1950 

